FIG. 1 depicts a portion of conventional head 1 including a conventional perpendicular magnetic recording (PMR) transducer 10 and conventional read transducer 40 separated by an insulator 6, as viewed from the air-bearing surface (ABS). The conventional head 10 is formed using a damascene approach, described below. For clarity, the conventional PMR transducer 10 is not drawn to scale. Also depicted is the substrate 2, which may be part of a body of a slider (not separately depicted in FIG. 1).
The conventional PMR transducer 10 includes a conventional first pole 12, alumina insulating layer 14, alumina underlayer 16 that may be considered part of the alumina insulating layer 14, a conventional PMR pole 18 that typically includes a seed layer (not shown), insulating layer 20, shield gap 26, top shield 28, and insulating layer 30. Note that in certain other embodiments, the top shield 28 may also act as pole during writing using the conventional PMR transducer 10. The conventional PMR pole 18 and the top shield 80 are surrounded by insulating layers 20 and 30, respectively. The conventional PMR pole 18 has sidewalls 22 and 24.
In conventional applications, the height of the conventional PMR pole 18 is typically less than approximately three-tenths micrometer. The conventional PMR pole 18 also has a negative angle such that the top of the conventional PMR pole 18 is wider than the bottom of the conventional PMR pole 18. Stated differently, the angle θ of the sidewalls is less than ninety degrees in the conventional PMR pole 18 of FIG. 1. A pole having this height and shape is desirable for use in PMR applications.
FIG. 2 is a flow chart depicting a conventional method 50 for fabricating the conventional PMR transducer 10 using a damascene process. For simplicity, some steps are omitted. The conventional method 50 is described in the context of the conventional PMR head 1. The conventional method 10 starts after formation of the first pole 12 and the alumina 14. The alumina underlayer 16 and insulating layer 20 are formed. Thus, the insulating layers 14, 16, and 20 may be part of a single, larger insulating layer. A mask is formed, via step 52. The mask is typically a reactive ion etch (RIE) mask having an aperture that is the same width as the top of the conventional PMR pole 18. A RIE is performed to form a trench in the insulating layer 20, via step 54. The trench in the insulating layer 20 has substantially the same shape as the conventional PMR pole 18. The trench is refilled using the material for the conventional PMR pole 18, via step 56. The material may be planarized, via step 58. Consequently, the conventional PMR pole 18 remains. Fabrication of the PMR head 1 is then completed, via step 60.
Although the conventional method 50 may be used to fabricate the conventional PMR pole 18, there are drawbacks. For example, the changes in the length of the RIE performed in step 54 results in varying thicknesses of the trench. Consequently, the height, h, of the conventional PMR pole 18 may vary. Such a variation between conventional PMR poles 18 is undesirable.
Accordingly, what is needed is an improved method for fabricating a PMR head.